Bottom feed - updraft gasification system

ABSTRACT

A gasification system for solid wastes having a thermal reactor and a mechanical gas cleaner, an indirect heat exchange cooler, and an electrostatic precipitator for cleaning and cooling the produced gas. Feed material is continuously fed to he central section of the thermal reactor above an air introduction manifold and nozzles and in an upward direction, forming a stratified charge. As feed material moves upward and outward from the reactor center it is reduced to ash. An agitator assures contact between the hot particulate product and hot gases resulting in gasification of the feed material and net movement to the sidewall of the thermal reactor, forming ash. The air introduction nozzles serve as a grate. Ash descends along the sidewall to the reactor base for removal. The mechanical cleaner has a high speed rotating brush-like gas separator element and scraper combination which removes condensed tars and particulates from the produced gas stream. The device is self cleaning in that condensed tars and particulates agglomerate on the high speed rotating bristle elements and, upon reaching adequate size and mass, are thrown off by centrifugal force to the cylindrical sidewall, where scrapers remove accumulated material which falls to the separator base for removal. An electrostatic precipitator having a cylindrical brush-like electrode suspended from one end by an insulated arm, removes remaining particles or aerosols from the product gas.

This case is a CIP of U.S. application Ser. No. 08/292,922 filed on Aug.18, 1994, now abandoned; which is a continuation of U.S. applicationSer. No. 08/032,642 filed Mar. 17, 1993, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to gasification of solid organic material.More specifically, the present invention relates to gasification oforganic solid material to produce combustible gas to be utilized forenergy production and/or recover chemical components from pyrolyzedorganic material.

2. Discussion of the Prior Art

Gasification to produce combustible gases from the destructivedistillation of organic solid materials is known in the prior art andentails using the heat of combustion of at east a portion of the organicmaterial to maintain a pyrolysis reaction. Organic material to begasified is introduced to the gasification reactor, typically from thetop, thereof. An oxygen containing gas such as air is introduced to thethermal reactor bellow the organic material to form a combustion zonewhere the residue of the gasification process is combusted to producethe heat required for the gasification reaction. The hot gases from thecombustion zone are forced upward through the mass of organic materialby the introduced air. The heated air and gases cause destructivedistillation of the organic material and the generation of hydrogen,carbon monoxide and other carbon-containing gases including carbohydrategases according to reactions such as the following:

    C.sub.x H.sub.y O.sub.z +O.sub.2 =C+CO+CO.sub.2 +C.sub.x1-xn H.sub.y1-yn O.sub.z1-zn

In an efficient gasification device in which the desired output is acombustible product gas, suitable for use in internal combustionengines, boilers, turbines or heating devices, the free carbon in theproducts of combustion should be minimized or effectively made zero.Further, the amount of carbon dioxide should be minimized.

An important aspect of the design of a thermal gasification reactor isthe provision for intimate contact of the newly introduced organicmaterial with the hot air and gases from the combustion zone to promoteefficient gasification while providing for the efficient removal ofcarbon-containing solid products from the gasification zone to thecombustion zone where they provide fuel for producing heat for thethermal reaction. Many organic materials can form large agglomeratemasses or clinkers under the conditions of operation of the gasificationreactor which can halt movement of material through the reactor andmoving parts such as agitators.

In U.S. Pat. No. 4,445,910 (1984), Zimmerman shows a pyrolysis systemfor generating gas and producing char particularly adapted forprocessing cellulosic waste material such as sawdust, wherein feedmaterial is fed upward into the base of the reactor chamber and air isfed radially around the chamber sidewall. Also disclosed is a system forcleaning the product gas. Although the Zimmerman system may be efficientfor the processing of finely divided material such as sawdust, materialswith larger particle sizes or which would tend to form clinkers undergasification conditions would be inappropriate for feeding the Zimmermanreactor due to the relatively restricted configuration of the solidsremoval mechanism. The Zimmerman system is directed toward carrying outa pyrolysis process rather than the gasification process of the presentinvention as the reactor configuration of Zimmerman will not react thechar into ash.

In U.S. Pat. No. 4,614,523 (1986), Soares discloses a down flow gasifierfor waste wood and biomass having downward directed air introductionnozzles and a reactor cooling jacket. The Soares system, however, is acomplicated structure, the gas offtake would be subject to clogging bydeposition of tars and particulates carried by the product gaseouseffluent when certain teed materials are employed, and many finematerials will restrict air flow through the bed.

In U.S. Pat. No. 4,971,599 (1990), Cordell et al. disclose a biomassgasifier with feed material being fed upward to the base of the reactor.The presence of a grate in the Cordell et al. reactor could lead toclogging by clinkers when certain feed materials are used.

Another problem encountered in solids gasification and thermaldistillation systems is the handling of particulate and tar ladengaseous effluent. Tars and particulates must be removed and the gascooled before it becomes a useful product for energy recovery.Particulate and condensed tars tend to clog conduits, coolers, andseparators. In U.S. Pat. No. 4,069,133 (1978), Unverferth shows arotating spiral assembly for cleaning an overhead conduit of a thermaldistillation unit and returning condensed tars and particulates back tothe process. The assembly of Unverferth does not employ any activecondensation and cleaning apparatus at the point of gaseous effluentexit from the distillation unit for removal of tar and particulates fromthe gaseous effluent for return to the distillation unit. The Zimmerman-910 patent shows a typical gas purification system employing extensivegas-liquid contact devices. These systems suffer from the disadvantagesof size, high energy losses, complexity, high liquid use, loading fromevaporated liquids, and clogging and maintenance problems.

These and other deficiencies of prior gasification systems are met inthe gasification system of the present invention. The gasificationthermal reactor of the present invention provides the capability ofprocessing a large variety of feed materials ranging from wood andbiomass materials to municipal solid waste, dewatered sewage sludge,discarded rubber from articles such as used tires, plastics, industrialprocess wastes, medical/hospital wastes, and the distillation of oilshales. The inventive system provides for feeding material continuouslythrough a conduit to the center of a central section of the thermalreactor and in an upward direction. As the feed material is conveyed byan auger system to the feed point, it is preheated through conduit wallsexposed to hot solids in the combustion zone. Preheated feed material isthen forced upward by subsequently introduced feed material into agasification zone, where it forms a stratified charge and is contactedwith upwardly traveling hot gases from the combustion zone and hotparticulate products of the gasification reaction. As feed materialmoves upward and outward from the center of the reactor it is reduced toash as a result of reaction with the upwardly moving oxidizing gas,resulting in less tar and oils in the output gaseous effluent than inother known gasifiers. An agitator assures efficient contact between thehot particulate product and hot gases resulting in gasification of thematerial and a net movement of hot particulate product to the sidewallof the thermal reactor. Since the complete volatilization of materialoccurs at this stage and the gas produced is partially volatilized, theoutput gaseous effluent from the thermal reactor contains less tars thanproduced from known gasifiers. This hot mixture of particulate materialand ash descends along the sidewall and around the feed conduit andbetween air introduction nozzles to the combustion zone. Due to theunique design of the air introduction nozzles, a conventional grate isnot required. The air introduction nozzles are directed radially inwardfrom a manifold integral with the inner surface of the reactor sidewallso as to function as a grate. Clinkers, however, can easily move throughthe nozzle structure since the nozzles are more widely spaced near thereactor wall. Clinkers formed near the center of the reactor slowly moveoutward toward the sidewall where they fall between the nozzles. Thenozzles direct air preheated by its travel through the hot manifold andnozzles downward into the combustion zone. For the reaction ofhydrogen-deficient fuels such as tires and coal, a preferred embodimentof the invention provides an automatic control system for injection ofwater with the preheated air by means of a water injection spray ringlocated within the annulus of the air preheat manifold. The waterprovides hydrogen and oxygen to the reactor when reacted with hightemperature char(963 degrees C. or higher). The reaction of hot carbonand water to form carbon monoxide and hydrogen assists in oxidation ofthe char(carbon), as the water causes oxidation of the carbon and morecomplete reduction to ash. The ash is created when the high temperaturepre-heated air reacts with the char to reduce the char to ash and thisreaction is enhanced when steam is present to produce the reaction.Injection of the water is controlled by means of a temperature sensorand when the measured temperature reaches a certain limit, means isprovided or proportional injection of the water to the manifold. Ash isremoved from the lower section of the reactor and a mechanical breakeris employed to break and comminute any agglomerates or clinkers whichwould otherwise impede ash removal. Clinkers are formed in the reactorwhen the ash produced has a low melting point. Any unreacted material inthe ash agglomerates is exposed for reaction as a result of thiscomminuting action. An agitator may also assist in the ash flow. Theinventive reactor avoids the use of a grate, as in Cordell et al. -599,which would be subject to clogging by clinkers in the descending solidmaterial, while avoiding a top-feeding system with its attendantcomplexities in removing product gaseous effluent as in the -523 patentto Soares.

The manner of feeding and distribution of the inventive reactor alsoincreases the energy present in the lower reaction zone by introducingfresh unreacted feedstock into the region. This fresh fuel acts toincrease the thermodynamic reaction rate in the inventive reactor andaccelerate the reduction of char to ash by providing energy for thisreaction. The volatilized compounds evolved from the fresh feedstockpartially combust and increase the reaction rate, additionally. Anycorresponding gasification of char in the Zimmermann -910 device willoccur slowly or not at all.

The inventive system provides for the efficient cooling and cleaning ofthe gaseous effluent without direct contact with liquids as in the -910patent to Zimmerman, resulting in a more efficient and reliable gastreating system. No additional gas loading from vaporized liquid ispresent and no clogging of liquid recycle and spray equipment can occur.The inventive high speed rotating brush-like gas separator element andscraper combination of the present invention efficiently removes tarsand particulates from an indirectly cooled gas stream without theproblems of direct liquid contact as discussed above. Cooling may beprovided by means of internally mounted cooling tubes, a cooling jacketon the exterior wall of the unit, or both cooling tubes and coolingjacket. Although the use of brush-like elements for gas separation areknown in the prior art, as shown by Hollingsworth, U.S. Pat. Nos.2,998,099 (1961) and 2,922,489 (1960), and Moore, U.S. Pat. No.5,111,547 (1992), the novel combination of high speed brush rotation anda wall scraper of the present invention provides for highly efficientgas separation in the difficult tar and particulate environment of thepresent invention. The device is self cleaning in that condensed tarsand particulates agglomerate on the high speed rotating bristle elementsand, upon reaching adequate size and mass are thrown off the bristle bycentrifugal force to the cleaner sidewall where scrapers removeaccumulated material, which in turn falls to the separator base forremoval. Provisions are made for recycle of separated tars andparticulates to the reactor, reducing by-products and improvingefficiency of the inventive system while increasing the heating value ofthe product gas. Automatic controls provide for safe and efficientoperation of the inventive thermal reactor.

A cooling module of known design is provided in the inventive system forcooling gaseous effluent leaving the mechanical separator, the coolingmodule being of an indirect heat exchange type to avoid the addition ofcooling fluid directly to the gas stream.

A novel electrostatic precipitator is provided to further removeremaining solid condensed particles and aerosols from the product gasstream. The electrostatic precipitator of the present invention is selfcleaning due to the non-rotating cylindrical brush-like configuration ofits charging electrode and the unique manner in which the electrode issuspended, i.e., vertically by one end from one end of an arm, the otherend of which is immersed in a temperature controlled oil bath andconnected to a power source via an insulator projecting through the baseof the oil bath. The oil bath is temperature controlled to prevent waterand other accumulations in the bath. Charged particles are forced to theoutside wall of the precipitator and flow therealong to a collectionpoint at the base of the precipitator due to the force of gravity,resulting in self cleaning of the collector electrode. The employment ofelectrostatically charged brush-type collector elements is known asshown in the dryer of Stickel, U.S. Pat. No. 2,780,009 (1957), butStickel does not teach the suspension system of the present inventionwhich allows for gravity induced self cleaning, nor does Stickel providewater jacket cooling or add cooling coils internally to the unit.Stickel does not contemplate the cleaning of conductive gases such asthose formed in the present inventive system where acetic acid and waterare present in a potentially explosive gas stream. In U.S. Pat. No.3,111,024 to Sarver, a vertically suspended brush-type gas separator isshown, but it is not electrostatically charged and has gas back flow andan active oscillator employed in its cleaning cycle. Provision is madein the inventive system to collect the tar and particle laden condensatefrom the base of the cooling module and the electrostatic precipitator,respectively, and to separate and remove condensed water, recycling thetars, oils, and particulates to the thermal reactor.

SUMMARY OF THE INVENTION

The present invention relates to a system for gasification of a widerange of solid organic materials to yield a useful product gas outputwhich overcomes gas cleaning and cooling problems and clogging solidsclogging problems in prior art gasification systems.

An object of the invention is to provide an organic solids gasificationsystem free from clogging by processed solids.

A further object of the invention is to provide a gasification systememploying indirect cooling of produced gas to avoid vapor loading andclogging or handling complexity problems of recirculating liquid spraysystems.

A still further object of the invention is to provide a gasificationsystem maintaining heat efficiency in preheating solids and air feed.

A still further object of the invention is to provide a gasificationsystem that permits regulation and balancing of air flow rate, and inputmaterial feed rate, while at the same time minimizing carbon and carbondioxide output and maximizing volume product gas output and quality.

Additional objects, advantages, and novel features of the invention willbecome apparent to those skilled in the art upon examination of thefollowing description or may be learned by practice of the invention.The objects and advantages of the invention may be realized and attainedby means of the instrumentalities and combinations particularly pointedout in he appended claims.

To achieve the foregoing and other objects, and in accordance with thepurpose of the present invention, as embodied and broadly describedwherein, the present invention may comprise: (a) a cylindrical thermalreactor with a tapering lower body, preferably conical or invertedpyramidal, housing an air manifold with downward directed air input thatsupports incoming solid waste material which is fed by an auger and feedsystem from below, upwardly from outlet into a central section of thethermal reactor above and spaced from the air manifold, (b) an airmanifold injection system with input air volume control (c) a clinkerbreaker system rotating about a horizontal axis to break up large solidparticulate by-products of the gasifier reaction, (d) a rotary agitationsystem operating above the air manifold and feed auger outlet, (e) thefeed auger having the rotating portion terminated a predetermineddistance below and short of the outlet, creating a seal to prevent lossof product gases, (f) a feedback and control system that senses thelevel of solid material in the reactor and varies and balances the augerinput rate against the air flow, and material consumption rates, (g) afeedback and control system that measures product gas pressure andvaries air injection and feed rates to maintain constant product gaspressure, (h) a feedback and control system that measures reactortemperature(s) and varies feed rate and air and/or water injection ratesto optimize the process, (i) a mechanical cleaner employing high speedrotating metallic brushes and a concentric and coaxial scraper mechanismto collect particulate build-up on the walls of the cleaner which istransferred from the brushes to the walls of the cleaner by centrifugalforce, (j) an electrostatic precipitator system employing chargedmetallic brushes for separation of particulates and aerosols from theproduct gas, (k) an electrically isolated precipitator brush supportsystem (l) an indirect heat exchange cooler for cooling process gasbetween the mechanical cleaner the electrostatic precipitator, (m) arecycle auger to return collected solids from the mechanical cleaner tothe thermal reactor, and (n) a recycle conduit to return condensed tarsand oils from the cooler and the electrostatic precipitator to thethermal reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form part ofthe specification, illustrate an embodiment of the present inventionand, together with the description, serve to explain the principles ofthe invention.

FIG. 1 shows a diagrammatic view in elevation of the entire gasificationsystem of the present invention.

FIG. 2 shows a detail view in elevation of a preferred embodiment of thefeeder input auger system of FIG. 1.

FIG. 3 shows a detail view in elevation of a preferred embodiment of thethermal reactor of FIG. 1.

FIG. 4a shows a view in elevation of a preferred embodiment of the airinput manifold of FIG. 3.

FIG. 4b shows a bottom detail plan view of a preferred embodiment of theair input manifold of FIG. 3.

FIG. 5 shows a detail view in elevation of the mechanical cleaner ofFIG. 1.

FIG. 6 shows a sectional view of the mechanical cleaner at A--A of FIG.1.

FIG. 7 shows a detail view in elevation of the finned tubing coolingcage of the mechanical cleaner of FIG. 5.

FIG. 8 shows a detail view in elevation of the electrostatic isolationand suspension system of the electrostatic precipitator of FIG. 1.

FIG. 9 shows a partial view in elevation of the gasification system ofthe present invention illustrating automatic solids and air feedcontrols systems.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a gasification system that employs a feedsystem, gasification reactor, a mechanical cleaner, a cooling module andan electrostatic precipitator, to convert waste products into burnablegas and a reduced volume of easily disposable ash. Waste products areintroduced into a sealed reactor vessel and agitated at an elevatedtemperature. Air inlet to the vessel is controlled by one of acombination of three different feedback system designs to result inpartial to complete oxidation of the waste materials and output of aparticulate-laden gaseous effluent. The gaseous effluent is mechanicallycleaned, cooled and electrostatically cleaned by additional apparatus toproduce a clean burning product gas. Particulates, tar and oils removedfrom the gaseous effluent of the gasification reactor are recycled backinto the thermal reactor for additional gas extraction. Water removedfrom the gaseous effluent is discharged.

A wide variety of solid or semi-solid organic feedstock which by itselfor in combination has a heating value of at least 5,000 BTU per poundare useful in the present invention. Usable feedstocks include sortedmunicipal and commercial waste, shredded paper, wood waste, dewateredsewage sludge, scrap tires, agricultural waste, automobile shredder"fluff", paint sludge, coal, oil field wastes and hydrocarboncontaminated soils, and oil shale. Liquid wastes may be mixed withsolids prior to processing in the inventive system.

Depending on the nature of the feedstock, either low BTU gas for energyproduction or a range of by-products such as diesel fuel and aspbalticmaterials (from tires or oil shale); ammonia(from many feedstocks);liquified gases such as hydrogen nitrogen, carbon dioxide (from manyfeedstocks) and various other compounds may be obtained as products ofthe inventive system.

Referring to FIGS. 1, 2, and 3, there is shown a cross section inelevation of the gasification system and details of the auger feedsystem and the thermal reactor, respectively, of the present invention.The gasification system 10 of the invention is fed by feeder input augersystem 12, which accepts waste material input and recycled solids, tarand oil for loading for the gasification system 10. Feeder input augersystem 12 includes top feeder bin 14 of a truncated inverted pyramidalconfiguration, feeding downward into a box-like lock hopper 16, ofconventional design, and subsequently to an obliquely oriented main feedauger 18.

Thermal reactor 20 has an inverted conically shaped lower portion 22,having conical wall 23, and a cylindrically shaped upper portion 24,having cylindrical wall 26. The upper portion of thermal reactor 20, issealed with cover plate 28. The lower portion of thermal reactor 20,terminates in ash discharge auger 30 and lock hopper (not shown). Uppercylindrical portion 24 includes upper section 32, and central section34. Lower section 36 is included in the lower part of upper cylindricalportion 24 and lower conical portion 22. Air input manifold 38, havingradially extending air introduction nozzles 40, is integral with theinner surface of cylindrical wall 26 so as to divide central section 34from lower section 36. Ash clinker breaker 44 is located in conicallower portion 22, above ash discharge auger 30. Reactor exit port 48 islocated in cover plate 28. Reactor conduit 50 is connected to thermalreactor 20 at reactor exit port 48.

Main feed auger 18 extends through conical wall 23, through lowersection 36 and discharges through feed auger outlet 52 upward intocentral section 34 along the central axis, thereof. Material agitator 54is located in central section 34 above and spaced from feed auger outlet52. The ash discharge auger 30 and lock hopper (not shown) are sealed tomaintain pressure in thermal reactor 20 and prevent the loss of gaseouseffluent.

Reactor conduit 50 contains internal rotating brushes 58 driven byhydraulic pipe cleaner drives 60 located at bends 62 in reactor conduit50. Other suitable drives may be used such as electric. Reactor conduit50 is connected to mechanical cleaner 70 at tangential input port 72,located a cylindrical base 74 of the mechanical cleaner 70. Mechanicalcleaner 70, includes lower conical section 76, located above tangentialinput port 72 of base 74 and upper cylindrical section 78 above conicalsection 76. Cover plate 82 forms the top of mechanical cleaner 70. Thebottom discharge 84 of mechanical cleaner 70 is open to allow forpassage of solids through solids auger return 85 for recycle to feedlock hopper 16.

Mechanical cleaner 70 houses high speed rotating metallic brush element86 having bristles 88 mounted on shaft 90. Brush element 86 revolves atabout 3000 revolutions per minute within a stationary finned coolingcage, 92 in upper cylindrical section 78. Harmonic balancer 93, adisk-shaped metallic element is attached at the lower end of shaft 90and serves to reduce vibration and whipping in brush-like element 86during high speed operation. In a typical installation the harmonicbalancer 93 is a steel disk or pulley about 2" thick and 3' in diameterand weighing about from 90 to 100 lb. Sizing of a particular balancer isdetermined by standard engineering practice. Upper scraper brushes 94rotate at a low speed outboard of the finned cooling cage 92. Upperscraper brushes 94 sweep the interior of upper cylindrical section 78,and lower scraper brushes 96 sweep the interior of lower conical section76 of the mechanical cleaner 70. The high speed brush element 86 aredriven by a hydraulic motor 98 mounted at the cover plate 82. The lowspeed upper and lower scraper brushes 94 and 96 are driven from thecylindrical base 74 of the mechanical cleaner 70 by a motor (not shown)at about 1 revolution per minute. The open bottom discharge 84 of themechanical cleaner 70 communicates with solids recycle circuit 100.Thermal reactor 20 and/or mechanical cleaner 70 may be wrapped inboiler-tube-type heat dissipating water jackets 102 and 104,respectively, as an additional mechanism for heat removal.

Mechanical cleaner conduit 106 connects output port 108 of themechanical cleaner 70 with indirect cooling module 120 at input port122. Cooling module 120 contains fluid cooled indirect heat exchangersof known construction(not shown). Condensate water exits cooling module120, through cooler drain 124, and drain conduit 126. Gas output port128 of the cooling module 120 is similarly connected by cooling moduleconduit 128 to electrostatic precipitator 130 at conical base 132 attangential input port 134.

Electrostatic precipitator 130 Is a vertically disposed, generallycylindrical structure having a conically shaped base 132 supportingcylindrical wall 136 capped with seal plate 138. Electrostaticprecipitator 130 also contains isolated and suspended stationary brushes140 having radially extending bristles 142 mounted on and attached toshaft 144 along its length, shaft 144 being suspended by one end fromisolation and suspension system 146 along the central vertical axis ofcylindrical wall 136. Isolation and suspension system 146, is secured toelectrostatic precipitator 130 at seal plate 138. A cooling jacket 139surrounds cylindrical wall 136 for additional cooling. Furtheradditional cooling is provided by internal cooling coils 141 locatedwithin the interior of the cylindrical structure. Product gas departsthe system 10 through product gas outlet port 148, located just belowseal plate 138, on cylindrical wall 136 of electrostatic precipitator130 and into product gas conduit 149.

Precipitator base 132 of the electrostatic precipitator 130 is connectedthrough condensate drain 150 and tar/oil/water conduit 152 to atar/oil/water separator 154 of known construction. Tar/oil/waterseparator 154 is connected by tar/oil recycle conduit 156 to main feedauger 18 at tar/oil recycle port 158, completing tar/oil recycle circuit160. The tar/oil/water separator 154 includes a water discharge port 162leading to discharge conduit 163.

Referring more particularly to FIG. 2, there is shown an elevation viewin detail of the feed input auger system of FIG. 1. Main feed auger 18of input auger system 12 serves as a feed conduit and is connected tothree sources of material; top feeder bin 14 connected to lock-hopper16, tar/oil recycle circuit 160, and solids auger return 85 of solidsrecycle circuit 100. Lock hopper 16 is joined to main feed auger 18 atthe auger's lower origin 166. Tar/oil recycle circuit 160 is joined tomain feed auger 18 at tar/oil recycle port 158. Solids auger return 85is joined to main feed auger 18 at solids recycle input port 168 locatedin auger wall 169. Main feed auger blades 170, rotating axially withinmain feed auger 18 are preferably of such diameter as to closely fitwithin auger wall 169 to maintain an upward feeding action for thesolids therein. Main feed auger blades 170 terminate a specifieddistance (about one and one-half auger blade diameters) short of thefeed auger outlet 52 (see FIG. 1). In a preferred embodiment an airinjector 171 is located in the vicinity of feed auger outlet 52 such asat the terminal point of feed auger blades 170 to provide for injectionof air into the feed material to assist in its movement to outlet 52 toprevent material packing in auger 18.

Referring more particularly to FIG. 3, there is shown an elevation viewin detail of a preferred embodiment of thermal reactor 20 of FIG. 1. Theconical shaped lower portion 22 of thermal reactor 20 contains ashdischarge auger 30 at its base. Ash clinker breaker 44 is located aboveand spaced from ash discharge auger 30 within conical portion 22. Airmanifold 38 and air inlet 172 are positioned near the bottom of thecylindrically shaped upper portion 24 of thermal reactor 20, dividingthe central section 34 from lower section 36. Refractory liner 173 maybe located on the inner wall of upper cylindrical portion 24 and may bemade of fire brick or suitable cast refractory. Material agitator 54 hasradially disposed agitator blades 174 located above and spaced from airinput manifold 38 and feed auger outlet 52. In a preferred embodiment,scraper blades 175 sweep the interior wall of upper section 32 ofthermal reactor 20, blades 175 being connected to and driven by rotatingshaft 176 of material agitator 54 rotating at from about 1 to 2revolutions per minute. In a further preferred embodiment rotating shaft176 extends into feed auger outlet 52 where it drives outlet auger 177.Coverplate 28 of cylindrical shaped upper portion 24 of thermal reactor20 contains reactor exit port 48 and agitator hydraulic drive motor 55driving shaft 176. Clinker breaker 44 acts as a fused materialcomminuter and includes a steel shaft which is hydraulically driven andoperates when ash discharge auger 30 is operated. Clinker breaker 44 hasradially extending blades of flat steel bar have varying lengthsselected to conform with the interior wall of conically shaped lowerportion 22 of reactor 20. The blades are preferably set at an angle ofabout 45 degrees in relation to the longitudinal axis of the shaft andare distributed along and around the shaft. Clinker breaker 44 acts notonly to break fused material to promote flow of solid materials throughreactor 20, but the agitation produced thereby promotes further reactionof unreacted solid material.

Referring to FIGS. 4a and 4b, there is shown an elevation detail viewand bottom detail view, respectively, of a preferred embodiment of theair input manifold system of the thermal reactor of FIG. 3. For claritycertain nozzles are deleted from FIG. 4a. FIG. 4a further illustrates anautomatic control system for supplying water to a spray head located inair manifold system 38. The air manifold system 38 is supplied with airor other oxygen-containing or oxidizing gas through air inlet 172.Temperature sensor 177 is connected by control line 178 to inlet watercontrol valve 179, which controls the addition of water to waterinjection spray head 180. Water injection spray head 180, havingdownwardly directed water nozzles 181, is located in the upper portionof annular chamber 182 of air manifold system 38. Annular chamber 182,which is rectangular in cross section, preferably has a height of about50% of the total diameter of manifold 38, air inlet 172 being located inthe upper portion thereof. Air manifold 38 has multiple nozzles, 40,which radiate inward from annular chamber 182 toward a central axis.Annular chamber 182 has multiple downward facing air outlets 183. Eachnozzle 40 has multiple downward facing air outlets 184. Nozzles 40 maybe of varying lengths to provide for desired air distribution and solidsflow.

Referring to FIG. 5, there is shown an elevation view in detail of themechanical cleaner of FIG. 1. Reactor conduit 50, which originates atthermal reactor 20 (see FIG. 1), joins the mechanical cleaner 70 at thetangential cleaner input port 185. Tangential port 185 is a preferredembodiment over port 72 of FIG. 1 and provides swirling gas flow upwardthrough the mechanical cleaner 70. Vertical drive shaft 186, originatingat and driven by a motor (not shown) from below mechanical cleaner 70,is connected by arms 188 to two sets of scraper brushes 96, which sweepthe inner wall of lower conical section 76. Scraper brushes 94 areconnected to drive shaft 186 by radially extending arms 189 and sweepthe inner wall of upper cylindrical section 78 of mechanical cleaner 70.Scraper brushes 94 have their bristled sections vertically staggered inorder to sweep substantially all of the inner wall of upper cylindricalsection 78. In cylindrical section 78, stationary tubing cooling cage 92is suspended just inboard of the scraper brushes 94. The tubing Coolingcage 92 surrounds high speed rotating brush-like element 86, powered byhydraulic drive motor 98, located on coverplate 82. The bottom ofmechanical cleaner 70 is open to bottom discharge 84 to discharge solidsto solids auger return 85 of recycle system 100 (see FIG. 1). Gasesdepart mechanical cleaner 70 through cleaner output port 108. In apreferred embodiment bristles 88 of brush element 86 are located alongshaft 90 so as to form a helix or double helix having an axis along theshaft. Shaft 90 is rotated in such a direction that rotating brushelement 86 provides a pumping action which assists in moving theparticle laden gaseous effluent from the lower section 76 to the uppersection 78 of mechanical cleaner 70.

Referring to FIG. 6, there is shown a plan view through section A--A ofFIG. 5 (the harmonic balancer, lower scraper brushes, and scraper armsare not shown). Upper scraper brushes 94 rotate outboard of stationaryfinned tubing cooling cage 92. High speed brushes 86 rotate inboard ofstationary finned tubing cooling cage 92. Reactor conduit 50 istangentially connected to the mechanical cleaner 70 at tangential port185 of cylindrical base 74.

Referring to FIG. 7, there is shown a detail view in elevation of thefinned tubing cooling cage of FIG. 5. Finned tubing cooling cage 92 haswater inlet 190, feeding into one of a series of vertical heatdissipating elements 192. Heat dissipating elements 192 are joined atthe base of the cooling cage 92 by circular lower tubing manifold 194.Heat dissipating elements 192 are similarly joined at the top of finnedtubing cooling cage 92 by circular upper tubing manifold, 196. Waterrises through the remaining heat dissipating elements 192 to uppertubing manifold 196, and departs finned tubing cooling cage 92 throughwater outlet 198, connected to the upper tubing manifold 196.

Referring to FIG. 8, there is shown a detail of the electrostatic brushsuspension and isolation system of the electrostatic precipitator ofFIG. 1. Stationary metallic brushes 140 serve as a negative eleotrodeand are suspended from the center of precipitator 130 (see FIG. 1) byconductive suspension arm 200 of isolation and suspension system 146,situated at the top of electrostatic precipitator 130. The conductivesuspension arm 200 terminates near the outer edge of precipitator 130 inan insulating anchoring mechanism 201, which is isolated from theremainder of the system by being immersed in an oil bath 202. Oil bath202 includes base 203 on which insulating anchoring mechanism 201 islocated, and sidewall 204. Temperature sensor 205, located in sidewall204, activates oil heater 206 to maintain oil bath 202 at a desiredtemperature. Brushes 140 terminate about 3 inches from cylindrical wall136. A high voltage/low amperage (25 to 50 KV DC) power supply(notshown) is connected to conductive support 200 positive to induce apositive charge on stationary brushes 140 inside of precipitator 130.Cylindrical wall 136 (see FIG. 1) serves as a negative electrode and isconnected to ground.

Referring to FIG. 9, there is shown a diagrammatic elevation view of theautomatic control system for operation of gasification system 10.Temperature sensor 210 is mounted on cylindrical wall 26 of thermalreactor 20 at a point approximately dividing upper section 32 andcentral section 34 so as to sense the temperature of the gasificationprocess in thermal reactor 20. Level sensor 212 is mounted oncylindrical wall 26 of thermal reactor 20 at a point spaced from sensor210 at about the same elevation as temperature sensor 210. Level sensor212 senses the solids material level in thermal reactor 20. Solids feedrate controller 214 is located in feed input auger system 12 so as tocontrol the rotational speed of main feed auger 18 such as bycontrolling a drive motor (not shown). Pressure sensor 216 is located atproduct gas outlet port 148 of product gas conduit 149 of electrostaticprecipitator 130. Air inlet controller 218 is connected to air valve 220in air feed conduit 222 connected in turn to air inlet 172 of air inputmanifold system 38 of thermal reactor 20. Temperature sensor controlline 224 connects temperature sensor 210 to solids feed rate controller214. Level sensor control line 226 connects level sensor 212 to solidsfeed rate controller 214. Pressure sensor control line 228 connectspressure sensor 216 with air inlet controller 218. Moderator watersupply conduit 240, having moderator water control valve 242, isconnected to air feed conduit 222. Moderator control line 234 connectstemperature sensor 210 with quench water control valve 242. Sensors 210,212, and 216, controllers 214 and 218, and valve 242, as well as controllines 224, 226, 228 and 234 may be electrical, pneumatic, or hydraulicin operation, as desired.

In operation, the main oblique feeder auger 18 is fed with wastematerials from the feeder bin 14 through lock hopper 16. The main feedauger 16 is also fed with solid by-products of the process transportedfrom solids recycle circuit 100. By-product tar and oil is loaded intothe main feed auger 16 from the tar/oil recycle circuit 160 or,alternatively, drained from the system. Lock hopper mechanisms of knownconstruction (not shown) are employed for waste material feed system 12and ash removal system 30, that isolate the interior of the thermalreactor 20 from the outside atmosphere to maintain pressure and toprevent the loss of produced gas. The main feed auger 18 is alsoterminated a predetermined distance below the main feed auger outlet 52to develop an intentional congestion of input material near the mouth ofthe main feed auger outlet 52, further sealing the system from theoutside atmosphere. Waste materials are introduced to the thermalreactor 20 immediately above air manifold 38, and immediately below andspaced from agitation blades 174, which stir the incoming material andgasified particulates. Air enters thermal reactor 20 from the bottom ofthe radial manifold nozzles 40 and is preheated, therein. This feedconfiguration generates a stratified material bed and promotesgasification of the material bed from the bottom, upwards. Spacesbetween the radial nozzles 40 of air manifold 38 permit the residueresulting from the gasification process to drop to the bottom 22 ofreactor 20 after passing through a clinker breaker 44, which reducesfused masses or clinkers (if present) to a finer sized passableaggregate.

In the preferred embodiment of manifold 38 (See FIG. 4a) a controlledamount of water is added through spray nozzles 181 of spray head 180 tothe upper portion of annulus 182. This is appropriate for the reactionof hydrogen deficient feed materials such as rubber tires and coal. Thewater may be either makeup fresh water or recirculated water from thegas cleaning and cooling system. The water provides hydrogen and oxygenwhen reacted with high temperature char at temperatures above 963degrees C. The reaction of carbon and water yields carbon monoxide andhydrogen which assists in oxidation of the char(carbon) since the watercauses oxidation of the carbon and its more complete reduction to ash.Temperature sensor 177 senses temperature in annulus 182 and transmits aproportional signal over line 178 to automatic control valve 179, whichcontrols water feed to spray head 180. Valve 179 is in the closedposition until the measured temperature of annulus 182 reaches apredetermined limit. (typically 1600 to 2000 degrees F., depending uponthe nature of the feedstock, particularly, the level of hydrogendeficiency in the feedstock) at which time valve 179 opens to an extentnecessary to allow introduction of sufficient water to maintain theannulus temperature at the desired temperature.

As gaseous effluent travels between thermal reactor 20 and mechanicalcleaner 70, particulates are deposited on the walls of reactor conduit50 connecting those two units. The deposited particulate is recoveredand recycled using cleaner brushes 56 inside of reactor conduit 50 thatmove the particulate to the cylindrical base 74 of mechanical cleaner70. The reactor overhead gas is tangentially injected into mechanicalcleaner 70 at cylindrical base 74. As the swirling gas rises withinmechanical cleaner 70, high speed rotating brushes 86 serve ascollection points for particulates and condensed tars extracted from thegas. Centrifugal force transfers resulting agglomerated deposits to theinterior wall of mechanical cleaner 70. The deposited particulates aredislodged from the wall of mechanical cleaner 70 by slow speed rotatingbrushes 94, causing the particulates to fall to the bottom discharge 84.A nominal film of particulate is continuously maintained on the interiorwall of mechanical cleaner 70 which prevents metal-to-metal contact withthe slow speed rotating metallic brushes 94. A preferred embodiment ofthe invention includes a finned tubing cooling cage 92 for heatextraction from the process gas and removal of heat introduced by thehigh speed rotating brush bristles. An alternate embodiment includeswrapping the exterior of the mechanical cleaner 70 in a water cooledjacket 104 to assist in the heat extraction process.

Cooling for the process gas continues as it passes through the coolingmodule 120, in route to the electrostatic precipitator 130. Upon exitingcooling module 120, the temperature of the product gas is below thevaporization (dew point) temperature of oils, tars and water previouslycarried by the gas. Condensates of those three species are collected atthe base of cooling module 120 and precipitator 130. After waterextraction, tar and oil is returned to main feed auger 16 for additionalprocessing by thermal reactor 20 or discharged for byproduct usage. Theprocess gas is further cooled and cleaned in electrostatic precipitator130, which removes aerosols from the gas stream producing a clean, coolproduct gas. Clean product gas exits the system at electrostatic gasoutlet port 148.

The feed rate of solids material to thermal reactor 20 is controlled bymeans of temperature sensor 210 and level sensor 212, operating onsolids feed rate controller 214. As the reactor temperature increases,temperature sensor 210 sends control signals over control line 224 tofeed auger controller 214, which acts on feed auger 18 to decreasesolids feed rate such as by reducing auger rotational speed. As thermalreactor temperature decreases, temperature sensor 210 sends controlsignals over control line 224 to feed auger controller 214, which actson feed auger 18 to increase solids feed rate. As the solids level inthermal reactor 20 increases, level sensor 212 sends signals overcontrol line 226 to solids feed auger controller 214 which reducessolids feed rate of main feed auger 18. As solids in thermal reactor 20decrease, level sensor 212 sends signals over control line 226 to solidsfeed auger controller 214, increasing the solids feed rate of main feedauger 18. As gas pressure at product gas port 148 in product gas conduit149 increases, pressure sensor 216 sends signals over control line 228to air inlet controller 218, which acts on air valve 220 in air feedconduit 222, decreasing the feed rate of air to air inlet 172 of airinput manifold 38 and thus to thermal reactor 20. As gas pressure inproduct gas port 148 decreases, pressure sensor 216 sends signals overcontrol line 228 to air inlet controller 218, which acts on air valve220 in air feed conduit 222, decreasing the feed rate of air to airinlet 174 of air input manifold 38 and thus to thermal reactor 20. Upontemperature sensor 210 measuring a preset maximum temperature such asthat temperature which would indicate a runaway reaction in thermalreactor 20, temperature sensor 210 sends signals over quench controlline 234 to quench water control valve 242 in water quench conduit 240.Water control valve 242 is in a closed position during normal operation,but, upon receiving a signal from temperature sensor 210 indicating amaximum temperature in thermal reactor 20, water control valve 242opens, allowing water to flow through water conduit 240 into air feedconduit 222, through air inlet 172 of air input manifold system 38 andinto thermal reactor 20 to slow the reaction, therein. Water may beadded to the thermal reactor to moderate the gasification process. Foroperation with low hydrogen fuels such as coal and tires, water may beadded continuously to supply hydrogen to the process. Temperature sensor210 may be a standard type of thermocouple. Level sensor 212 may be avibrating reed type level sensor.

Typical waste solids feed rates for the inventive gasification systemare from 300-6000 lb/hr depending on particle size, heat content, andwater content of the feed. Solids feed is preferably in the range offrom 10-80 lb/cu. ft. with a particle size of less than two inches andless than 30% moisture. An air input to solids feed ratio of about 1.6to 1.0 to about 2.0 to 1.0 pounds solid fuel to pounds of air istypically maintained, depending on the particular solid fuel. The systempreferably operates at slightly over ambient atmospheric pressure, whichis advantageous over many gasification systems which operate at higherpressures, requiring more expensive apparatus.

The preferred design limits for the thermal reactor of the Presentinvention are a minimum of 3 ft. to a maximum of 16 ft. in internaldiameter, and a minimum of 6 ft. to a maximum of 34 ft. in height. For athermal reactor within these size parameters, a maximum feed rate of10,000 lbs./hr. and a minimum feed rate of 250 lbs./hr. arecontemplated. The operating pressure is about atmospheric, e.g., thatwhich enables product gas flow through the inventive system. Input airvolume requirements range from 300 CFM to 2,400 CFM for the preferredthermal reactor. The operating temperature of the thermal reactor of thepresent invention is typically from a low of about 1000 degrees F. toabout 2400 degrees F., with a preferred maximum temperature of about1,600 degrees F., measured in the vicinity of the top of the inlet airnozzles 40 in the thermal reactor. Output product gas temperature isabout 50-100 degrees F., depending on ambient temperature and userequirements of the gas product. It has been found that gasification inthe inventive gasification system results in product gas with a highercombustibles content and thus a higher heating value than known priorart waste solids gasifiers, resulting in a product gas heating value(with wood waste as the feedstock) of from about 176 to about 200BTU/st.cu.ft., which is substantially higher than the typical wood gasheating value of about 150 to 160 BTU/st.cu.ft.(See T. Reed and D.Jantzen, GENGAS, Tipi Workshop Book, Alienspark, Colo. (1982))

Intermediate temperatures in the system depend on the nature of thesolids feedstock and the raw gas output from the thermal reactor. As avariety of cooling mechanisms are provided, such as exposed metalconduits, cooling jackets, cooling cages, and other indirect heatexchange equipment, the intermediate temperatures may be manipulated asdesired. It is generally considered desirable to cool the raw processgas as early in the cleaning process as practicable. It is normallydesirable to maintain a very substantial reduction of temperature in theprocess gas by the time it leaves the mechanical cleaner. Waste heatfrom cooling elements may be recovered for other uses, increasingoverall efficiency of the system.

In an example of operation of the inventive gasification system, for asolids feed rate of 6000 lbs/hr of 20 lb. per cu. ft. material with aBTU heating value if 6000 BTU per lb., a gas output of 2400 std. cu. ft.per min. with a BTU value of 21.6 MM BTU/hr equivalent to a power outputof 1800-2400 KWHr is realized.

Table No. 1 presents analysis of product gas and calculated heatingvalue thereof for the inventive gasification system operated withinnormal parameters with a feedstock of wood waste having from 10 to 15%moisture content.

                  TABLE 1                                                         ______________________________________                                        Product Gas Energy content                                                    SAMPLE NO. 1        SAMPLE NO. 2                                              GAS    VOL %    HHV     LHV   VOL %  HHV   LHV                                ______________________________________                                        H2     1.36     4.45    3.77  3.45   11.29 9.55                               CO     28.57    92.57   92.57 34.04  110.29                                                                              110.29                             CH4    4.25     43.35   39.06 4.83   49.27 44.39                              C2H4   1.26     20.36   19.09 1.08   17.45 16.36                              HIGH   0.17     3.40    3.15  0.10   17.45 16.36                              CH                                                                            INERT  64.39                  56.50                                           BTU/            164.13  157.82       190.30                                                                              182.44                             SCF                                                                           ______________________________________                                    

Table 2 presents gasification system mass and energy balance estimateswhen processing waste wood.

                                      TABLE 2                                     __________________________________________________________________________    Material Balance Estimates for Gasification System Processing Waste           Wood and Municipal Refuse                                                     PARAMETER UNITS  WASTE WOOD                                                                             MUNICIPAL REFUSE                                    __________________________________________________________________________    Inerts Content                                                                          % by Volume                                                                          3.0      10.0                                                Moisture Content                                                                        % by Volume                                                                          10.0     30.0                                                Amount Processed                                                                        lbs/hour                                                                             300.0    250.0                                               Inerts Input                                                                            lbs/hour                                                                             9.0      25.0                                                Moisture Input                                                                          lbs/hour                                                                             60.0     75.0                                                Condensate Water                                                                        lbs/hour                                                                             50.0     56.8                                                Stack Moisture                                                                          lbs/hour                                                                             10.0     18.2                                                Solids Output                                                                           lbs/hour                                                                             9.0      25.0                                                Inerts Output                                                                           lbs/hour                                                                             8.25     25.0                                                Carbon Output                                                                           lbs/hr 0.75     1.85                                                Tar Production                                                                          cf/lb feed                                                                           7.6      15.6                                                Air Flow Rate                                                                           cf/hour                                                                              2280.    3900.                                               Gas Flow Rate                                                                           cf/lb feed                                                                           25.0     46.5                                                Gas Flow Rate                                                                           cf/hour                                                                              7500.    11625.                                              __________________________________________________________________________

Table 3 presents gasification system mass and energy balance estimateswhen processing municipal refuse.

                                      TABLE 3                                     __________________________________________________________________________    Energy Balance Estimates for Gasification System Processing Waste             Wood and Municipal Refuse                                                                     UNITS   WASTE MUNICIPAL                                       CATEGORY                                                                              VARIABLE                                                                              EMPLOYED                                                                              WOOD  REFUSE                                          __________________________________________________________________________    Fuel Parameter                                                                        Feed Rate                                                                             lbs/hour                                                                              300   250                                                     Heating Value                                                                         Btu/lb  6,000 9,000                                                   Heat Input                                                                            Btu/hour                                                                              1,800,000                                                                           2,250,000                                       Gas Flow                                                                              Air Flow AP                                                                           in H.sub.2 O                                                                          0.5   1.0                                             Parameter                                                                             Air Flow Rate                                                                         cf/min  38    52                                                      Gas Flow AP                                                                           in H.sub.2 O                                                                          1.0   1.0                                                     Gas Flow Rate                                                                         scf/min 125   155                                             Gas Stream                                                                            Flow Rate                                                                             scf/min 125   155                                             Parameter                                                                             Heating Value                                                                         Btu/scf 180   180                                                     Heat Output                                                                           Btu/hour                                                                              1,250,000                                                                           1,675,006                                       Thermal Heat Output                                                                           Btu/hour                                                                              1,350,000                                                                           1,675,000                                       Efficiency                                                                            Heat Input                                                                            Btu/hour                                                                              1,800,000                                                                           2,250,000                                               Efficiency                                                                            %       75    74                                                      Output/Input                                                          __________________________________________________________________________

The particular sizes and equipment discussed above are cited merely toillustrate a particular embodiment of this invention. It is contemplatedthat the use of the invention may involve components having differentsizes and shapes as long as the principles, i.e., low pressuregasification in a rising stratified bed surrounded by descendinggasified solids, efficient handling of solids, ash and condensates, gascleaning, and gas cooling as described above are followed. It isintended that the scope of the invention be defined by the claimsappended hereto.

I claim:
 1. A gasification system comprising:a. a generally cylindricalthermal reactor having a vertical central axis and a vertical sidewalland having an upper section, a central section, and a lower section,said upper section having closure means at an upper end thereof; b.means for feeding solid carbonaceous material to said thermal reactor;c. means for preheating and feeding oxidizing gas such as air located soas to divide said central section from said lower section, said meansfor preheating and feeding oxidizing gas comprising an annular gaspreheat manifold integral with and extending along the lower portion ofsaid vertical sidewall of said central section of said thermal reactorand having an inlet nozzle communicating with said preheat manifold,said means for preheating and feeding oxidizing gas further comprising aplurality of radially extending oxidizing gas feed nozzles convergingtoward said central axis, spaced along and in fluid communication withsaid gas preheat manifold and having means thereon defining a pluralityof oxidizing gas outlets; d. said solid material feeding meanscomprising a solid material feed conduit having an inlet, an outlet, anda rotating auger located therein, said inlet being connected to a sourceof solid material exterior to said thermal reactor, said outlet beingspaced above said oxidizing gas feed nozzles and so disposed andorientated as to direct introduction of solid material into said thermalreactor within said central section substantially along said centralaxis in an upward direction; e. means for discharging spent solidslocated in said lower section; f. said solid material feed conduit beingin heat transfer contact with spent solids as they descend toward saidspent solids discharge means, g. means for comminuting fused materiallocated in said lower section, h. means defining a particle ladengaseous effluent exit port located in said closure means; i. means forcleaning and cooling said particle laden gaseous effluent operativelyconnected with said gaseous effluent exit port of said thermal reactor;and j. means for separating particulate material from said particleladen gaseous effluent,whereby, said solid material is introduced intosaid thermal reactor by said feeding means and is thermolyticallydecomposed forming a particle laden gaseous effluent and a solidresidue, and whereby said particle laden gaseous effluent is directed tosaid cleaning means wherein said particles are separated from saidgaseous effluent, and whereby said gaseous effluent is directed to saidcooling means wherein said gaseous effluent is separated into condensateand product gas.
 2. The gasification system of claim 1 wherein saidcooling means and separation means comprise:a. a mechanical cleaneroperatively connected with said thermal reactor, b. a cooling moduleoperatively connected with said mechanical cleaner, and c. anelectrostatic precipitator operatively connected to said coolingmodule;whereby said particle laden gaseous effluent is directed throughsaid mechanical cleaner, and whereby said particles are separated fromsaid gaseous effluent, said gaseous effluent being directed through saidcooling module and into said electrostatic precipitator, and wherebysaid gaseous effluent is separated into said condensate and said productgas.
 3. The gasification system of claim 1 wherein said lower section isan inverted conically shaped wall and said spent solids discharge meansfurther comprises an ash discharge auger located at the base of saidlower section, said comminuting means being an ash clinker breakerlocated above said ash discharge auger.
 4. The gasification system ofclaim 1 wherein said oxidizing gas outlets are facing downward.
 5. Thegasification system of claim 1 wherein said thermal reactor furthercomprises agitation means located in said central section, above andspaced from said circular oxidizing gas feed manifold for agitating anddistributing said solid feed material as it enters said central sectionfrom said feed conduit.
 6. The gasification system of claim 5 whereinsaid agitation means comprises a rotating agitator shaft located alongsaid axis and a plurality of perpendicular agitation blades extendingradially across said central section.
 7. The gasification system ofclaim 6 further comprising scraper means located in said upper sectionso positioned as to sweep the inner surface of said upper section ofsaid wall.
 8. The gasification system of claim 7 wherein said scrapermeans comprise a plurality of scraper blades and radially extendingarms, said scraper means being mounted on and driven by said rotatingshaft by means of said arms.
 9. The gasification system of claim 1further comprising temperature sensing means located in said centralsection of said thermal reactor for sensing the operating temperature insaid reactor and feed control means responsive to said temperaturesensing means for controlling said solid material feeding means, saidfeed control means being so adapted as to increase solids feed rate tosaid thermal reactor upon said temperature sensing means sensing adecrease in temperature in said thermal reactor and to decrease solidsfeed rate to said thermal reactor upon said temperature sensing meanssensing an increase in temperature in said thermal reactor.
 10. Thegasification system of claim 1 further comprising level sensing meanslocated within and near the top of said central section of said thermalreactor for sensing the level of solids charge therein and feed controlmeans responsive to said level sensing means for controlling said solidmaterial feeding means, said feed control means being so adapted as toincrease solids feed rate to said thermal reactor upon said levelsensing means sensing a decrease in the solids charge level in saidthermal reactor and to decrease solids feed rate to said thermal reactorupon said level sensing means sensing an increase in solids charge levelin said thermal reactor.
 11. The gasification system of claim 2 furthercomprising pressure sensing means for sensing product gas pressure andlocated in a product gas conduit connected to said electrostaticprecipitator and air feed control means for controlling said oxidizinggas feeding means, said air feed control means being so adapted as toincrease oxidizing gas feed rate to said thermal reactor upon saidpressure sensing means sensing a decrease in product gas pressure and todecrease oxidizing gas feed rate to said thermal reactor upon saidpressure sensing means sensing an increase in product gas pressure. 12.The gasification system of claim 1 further comprising a cooling jacketintegral with said vertical wall.
 13. The gasification system of claim 2further comprising a reactor conduit connecting said upper section ofsaid thermal reactor with said mechanical cleaner for conducting saidparticle laden gaseous effluent from said thermal reactor to saidmechanical cleaner.
 14. The gasification system of claim 13 furthercomprising internal rotating brushes axially located in said reactorconduit for maintaining flow of said particle laden gaseous materialfrom said thermal reactor to said mechanical cleaner.
 15. Thegasification system of claim 2 wherein said mechanical cleaner furthercomprises upper and lower sections, a generally cylindrical sidewallhaving a vertical central axis and forming said upper section, and ahigh speed rotating brush-like element located along said axis in saidupper section.
 16. The gasifier system of claim 15 wherein said highspeed rotating brush element is cylindrical in shape having a high speedrotary shaft disposed along said axis and bristles extending radiallyfrom and attached to said high speed rotary shaft.
 17. The gasificationsystem of claim 16 wherein said bristles on said high speed rotatingbrush element are so disposed as to form a helix having an axis alongsaid high speed rotating shaft and operable to assist in moving saidparticle laden gaseous effluent from said lower section to said uppersection.
 18. The gasification system of claim 17 wherein said high speedrotating brush element further comprises a harmonic balancer located ata lower end of said high speed rotating shaft and drive means located atan upper end of said high speed rotary shaft.
 19. The gasificationsystem of claim 15 wherein said mechanical cleaner further comprisesscraping means located in said upper section of said mechanical cleanerso disposed as to sweep the inner surface of said cylindric wall. 20.The gasification system of claim 19 wherein said scraping means furthercomprises scraper blades to sweep said cylindrical wall, support membersto support said scraper blades, and a low speed rotating shaft connectedto low speed drive means for rotating said scraping means resulting insaid cylindrical wall sweeping, said support members being radiallyattached to said low speed rotary shaft.
 21. The gasification system ofclaim 20 wherein said scraping means further comprise brushes disposedon and extending along partial lengths of said scraper blades, saidbrushes being so arranged as to collectively sweep the entire surface ofsaid cylindrical wall along the length of said scraper blades.
 22. Thegasification system of claim 20 wherein said lower section of saidmechanical cleaner comprises an inverted truncated conical sidewallportion located below and connected with said upper suction and acylindrical sidewall portion located below and in communication withsaid conical sidewall section.
 23. The gasification system of claim 22wherein said scraping means further comprise lower scraper blades andlower support members mounted on said low speed rotating shaft, saidlower scraper blades being so positioned as to sweep the inner surfaceof said inverted truncated conical sidewall portion of said lowersection of said mechanical cleaner.
 24. The gasification system of claim23 further comprising a tangential inlet for particle laden gaseouseffluent located in said cylindrical sidewall portion of said lowersection of said mechanical cleaner for inducing swirl in the gaseouseffluent as it travels upward within said mechanical cleaner, said inletbeing in operative communication with said thermal reactor.
 25. Thegasification system of claim 15 further comprising a mechanical cleanerconduit in fluid communication with said upper section of saidmechanical cleaner for removing cleaned gaseous effluent from saidmechanical cleaner, said mechanical cleaner conduit being in fluidcommunication with said cooling module.
 26. The gasification system ofclaim 20 further comprising a cooling jacket integral with saidcylindrical wall of said upper section of said mechanical cleaner and acooling cage located in said upper section coaxially between said highspeed rotating brush-like element and said scraper blades.
 27. Thegasification system of claim 2 wherein said electrostatic precipitatorcomprises a generally cylindrical sidewall having a vertical centralaxis, an electrode disposed as a generally cylindrical metallicbrush-like element having a central shaft and bristles extendingradially and substantially perpendicular to said central shaft, saidcentral shaft being suspended along said vertical central axis, and apower supply so disposed as to provide negative charge to said electrodeand a positive charge to said cylindrical wall.
 28. The gasificationsystem, of claim 27 wherein said bristles extend substantially acrossthe internal diameter of said electrostatic precipitator andsubstantially perpendicular to said cylindrical wall.
 29. Thegasification system of claim 28 wherein said electrostatic precipitatorfurther comprises an inverted truncated conical base below saidcylindrical sidewall, a tangential inlet connected to and in fluidcommunication with a cooling module conduit connected with said coolingmodule for introduction of cooled gaseous effluent from said coolingmodule to said electrostatic precipitator said tangential inlet inducingswirl in the gaseous effluent as it travels upward within saidelectrostatic precipitator.
 30. The gasification system of claim 27wherein said electrostatic precipitator further comprises suspensionmeans for suspending said electrode, said suspension means comprising athermostatically controlled heated oil bath having a base and asidewall, and insulator element attached to said base, means forattaching a suspension arm to said insulator element and said electrode,and means for attaching a lead from said power supply through saidinsulator to said suspension arm.
 31. The gasification system of claim 2further comprising solids recycle means operatively connected with thebase of said mechanical cleaner and said feed means for returningseparated particulates from said mechanical cleaner to the gasificationthermal reactor.
 32. The gasification system, of claim 31 wherein saidsolids recycle means comprises a solids conduit connected with saidmechanical cleaner and said feeding means, and an auger axially locatedin said solids conduit for moving said separated particulates into saidfeeding means.
 33. The gasification system of claim 2 further comprisingtar recycle means operatively connected with the base of said coolingmodule, said base of said electrostatic precipitator, and said feedingmeans for returning separated tar, oil, and suspended particulates fromsaid cooling module and said electrostatic precipitator to saidgasification thermal reactor.
 34. The gasification system of claim 33wherein said tar recycle means comprises a tar/water separator, anelectrostatic precipitator drain conduit connecting said base of saidelectrostatic precipitator and said tar/water separator, a coolingmodule drain conduit connecting said cooling module and said tar/waterseparator, a water drain conduit connected to a lower section of saidtar/water separator, and a tar recycle conduit connected between anupper section of said tar/water separator and said feeding means forrecycling tar, oil, suspended particulates from said tar/water separatorto the gasification thermal reactor.
 35. The gasification system ofclaim 9 further comprising quench means responsive to said means forsensing temperature and so adapted as to introduce quench water intosaid oxidizing gas feed means upon said temperature sensing meanssensing a certain predetermined high temperature in said thermalreactor.
 36. The gasification system of claim 9 further comprising awater spray head located within said gas preheat manifold, temperaturesensing means located within said gas preheat manifold, and meansresponsive to said temperature sensing means for controlling theintroduction of water to said preheat manifold through said water sprayhead, said water introduction control means being so adapted as toinitiate the introduction of water into said gas preheat manifold uponsaid preheat manifold reaching a predetermined temperature as determinedby said temperature sensing means.
 37. The gasification system of claim36 wherein said water spray head is in the form of a ring located withinsaid annular gas preheat manifold and substantially concentrictherewith.
 38. The gasification system of claim 37 wherein the verticalheight of said annular gas preheat manifold is about 50 per cent of theoverall diameter of said thermal reactor.
 39. The gasification system ofclaim 38 wherein said spray head is located in the upper portion of saidannular gas preheat manifold and includes downward-directed nozzles forspraying water downward into the lower portion of said manifold.
 40. Agasifying thermal reactor comprising:a. a generally cylindrical sidewallhaving a vertical central axis and further having an upper section, acentral section, and a lower section, said upper section having closuremeans at an upper end thereof; b. means for feeding solid carbonaceousmaterial to said thermal reactor; c. means for preheating and feedingoxidizing gas, such as air, located so as to divide said centralsection, from said lower section, said means for preheating and feedingoxidizing gas comprising and annular gas preheat manifold integral withand extending along and substantially concentric with a lower portion ofthe wall of said central section of said thermal reactor and having aninlet nozzle communicating with said preheat manifold, said means forpreheating and feeding oxidizing gas further comprising a plurality ofradially extending oxidizing gas feed nozzles converging toward saidcentral axis, spaced along and in fluid communication with said gaspreheat manifold and having means thereon defining a plurality ofoxidizing gas outlets, d. said solid material feeding means comprising asolid material feed conduit having an inlet, an outlet, and a rotatingauger located therein, said inlet being connected to a source of solidmaterial exterior to said thermal reactor, said outlet being spacedabove said oxidizing gas feed nozzles and so disposed and orientated asto direct introduction of solid material into said thermal reactorwithin said central section substantially along said central axis in anupward direction; e. means for discharging spent solids located in saidlower section; f. said solid material feed conduit being in heattransfer contact with spent solids as they descend toward said spentsolids discharge means; g. means for comminuting fused material locatedin said lower section; and h. means defining a gaseous effluent exitport communicating with said upper section;whereby, said solid materialis introduced into said thermal reactor by said feeding means and isthermolytically decomposed, forming a particle laden gaseous effluentand a solids residue.
 41. The gasifying thermal reactor of claim 40wherein said lower section is an inverted conically shaped wall and saidspent solids discharge means further comprises an ash discharge augerlocated at the base of said lower section, said comminuting means beingan ash clinker breaker located above said ash discharge auger.
 42. Thegasifying thermal reactor of claim 40 wherein said oxidizing gas outletsare facing downward.
 43. The gasifying thermal reactor of claim 40wherein said thermal reactor further comprises agitation means locatedin said central section, above and spaced from said circular oxidizinggas feed manifold for agitating and distributing said solid feedmaterial as it enters said central section from said feed conduit. 44.The gasifying thermal reactor of claim 43 wherein said agitation meanscomprises a rotating agitator shaft located along said axis and aplurality of perpendicular agitation blades extending radially acrosssaid central section.
 45. The gasifying thermal reactor of claim 44further comprising scraper means located in said upper section sopositioned as to sweep the inner surface of said upper section of saidwall.
 46. The gasifying thermal reactor of claim 45 wherein said scrapermeans comprise a plurality of scraper blades and radially extendingarms, said scraper means being mounted on and driven by said rotatingshaft by means of said arms.
 47. The gasifying thermal reactor of claim40 further comprising temperature sensing means located in said centralsection of said thermal reactor for sensing the operating temperature insaid reactor and feed control means responsive to said temperaturesensing means for controlling said solid material feeding means, saidfeed control means being so adapted as to increase solids feed rate tosaid thermal reactor upon said temperature sensing means sensing adecrease in temperature in said thermal reactor and to decrease solidsfeed, rate to said thermal reactor upon said temperature sensing meanssensing an increase in temperature in said thermal reactor.
 48. Thegasifying thermal reactor of claim 40 further comprising level sensingmeans located within and near the top of said central section of saidthermal reactor for sensing the level of solids charge therein and feedcontrol means responsive to said level sensing means for controllingsaid solid material feeding means, said feed control means being soadapted as to increase solids feed rate to said thermal reactor uponsaid level sensing means sensing a decrease in the solids charge levelin said thermal reactor and to decrease solids feed rate to said thermalreactor upon said level sensing means sensing an increase in solidscharge level in said thermal reactor.
 49. The gasifying thermal reactorof claim 40 further comprising a cooling jacket integral with saidvertical wall.
 50. The gasifying thermal reactor of claim 47 furthercomprising quench means responsive to said means for sensing temperatureand so adapted, as to introduce quench water into said oxidizing gasfeed means upon said temperature sensing means sensing a certainpredetermined, high temperature in said thermal reactor.
 51. Thegasifying thermal reactor of claim 40 further comprising a water sprayhead located within said gas preheat manifold, temperature sensing meanslocated within said gas preheat manifold, and means responsive to saidtemperature sensing means for controlling the introduction of water tosaid preheat manifold through said water spray head, said waterintroduction control means being so adapted as to initiate theintroduction of water into said gas preheat manifold upon said preheatmanifold reaching a predetermined temperature as determined by saidtemperature sensing means.
 52. The gasifying thermal reactor of claim 51wherein said water spray head is in the form of a ring located withinsaid annular gas preheat manifold and substantially concentrictherewith.
 53. The gasifying thermal reactor of claim 52 wherein thevertical height of said annular gas preheat manifold is about 50 percent of the overall diameter of said thermal reactor.
 54. The gasifyingthermal reactor of claim 52 wherein said spray head is located in theupper portion of said annular gas preheat manifold and includesdownward-directed nozzles for spraying water downward into the lowerportion of said manifold.